The present invention relates to video decoding, and more particularly, to an entropy decoding apparatus with context pre-fetch and miss handling and an associated entropy decoding method.
The conventional video coding standards generally adopt a block based coding technique to exploit spatial and temporal redundancy. For example, the basic approach is to divide a source frame into a plurality of blocks, perform prediction on each block, transform residuals of each block, and perform quantization, scan and entropy encoding. Besides, a reconstructed frame is generated in an internal decoding loop of the video encoder to provide reference pixel data used for coding following blocks. For example, inverse quantization and inverse transform may be included in the internal decoding loop of the video encoder to recover residuals of each block that will be added to predicted samples of each block for generating a reconstructed frame.
Generally speaking, a video decoder is used to perform an inverse of a video encoding operation performed at the video encoder. For example, the video decoder is equipped with functions, including entropy decoding, inverse quantization, inverse transform, intra prediction, motion compensation, etc., for recovering residuals of each block and generating a reconstructed frame. The video decoder performance, however, is bounded by entropy decoding performance due to a data dependency issue. Furthermore, a large and complex context table makes the problem become worse.